Widows 8 After Sign In is Constantly Re-Starting.

Having no knowledge of Windows 8 my grown up daughter has brought me her laptop saying fix this dad, but I am used to XP and Vista.
She said that last week when she turned the laptop on a HP Pavilion with touch screen it start running windows updates but it went on and on for over an hour and she finished up having to press the on/ off button to stop it.
Now when it's turned it loads up to the login screen and after entering her password it starts up to desktop but the icons are just white and the icons start to load at bottom right corner then within a second it flashes and starts all over again and so unable to get into settings are anything.
Any help would be appreciated, thanks in advance.

Hi All,
I've found away to run safe mode and the PC runs ok without it flashing and restarting and managed to Run a Norton full scan which was ok. I also tried to run System Restore at different restore points but each time it stated that it did not complete successfully. On one attempt when it finished it stated that System Restore failed to extract the file ( C:\Program Files (x86) Hewlett-Packard\HP Health Check\ Active Check from the restore point . I also ran hardware diagnostic and everything showed ok.
The next option to me seems to be restore back to default settings or run the refresh option which uninstalls windows then reinstalls it. It seems that there's a file issue so also wondered if I should run chkdsk/R first, anything I do will have to be while I am in Safe Mode so would appreciate any info as I feel a bit out of my depth at the moment.

Hi All,
Just to conclude this post, I found that from the login screen I pressed ctrl alt del which put the power button on screen. Holding down the shift key while touching the power button and choosing restart the laptop rebooted into advanced settings from which I choose safe mode,I managed to back up all personal files. Before closing it down I checked device manager for any error's but there were no yellow exclamation marks so I closed it down. Next I powered it back up and kept tapping F11 key into system recovery and followed the on screen menu, within 45 minutes it was back up and running having filled out the original start registration and all that's left to do is download the Norton 360 and personalise Windows 8. For me this was my best choice I would have like to have solved the problem but my search enquiries were limited.
Thanks to Jock1e who took the time and trouble to try and help with my PC problem "Thank You"
Regards
OldRed